<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <script src="./jQ.js"></script>
    <!-- <script src="./jquery-3.4.1.js"></!-->
</head>

<body>

    <script>
        // console.log($, jQuery, $ == jQuery);
        // console.log($("div"));
        // console.log($("li"));
        // console.log($(".test1"));
        // // console.log($(), $([1, 2, 3]));
        // console.log($("<div>div1</div><div>div2</div>"));

        $(function() {
            let div = document.getElementById("demoID");
            console.log(div);
        })
    </script>
    <div class="test1">我是div1</div>
    <div id="demoID">我是div2</div>
    <li>我是li1</li>
    <li class="test1">我是li2</li>
</body>

</html>